Question

trei veverite au cules alune.cate alune a cules fiecare stiind ca doua cate doua au cules 42,37 si 21 alune?

Answer 1

a+b = 42  ; a+c = 37 ; b+c = 21

a+b+a+c = 42+37 <=> 2·a + (b+c) = 79 <=> 2·a +21 = 79 <=> 2·a = 79-21

2·a = 58 => a = 58:2 => a = 29

b = 42-a = 42-29 => b = 13

c = 21-b = 21-13 => c = 8

c = 37-a = 37-29 = 8, corect.